The Economist Gets Climate Sensitivity Mostly Wrong

Natural variability is a funny thing. And climate change deniers seem to have gotten all wrapped around the axle about it lately. After cherry picking 1998 as both the then hottest year on record and the strongest El Nino in decades, deniers have been desperately trying to claim that the Earth has been cooling down ever since. Of course their arguments are as bunk as bunk can be. The decade of 2000-2010 was the hottest decade on record. This despite falling solar activity (the deniers tried to claim solar activity was rising, but it wasn’t), increasing levels of sunlight reflecting SO2 in the stratosphere, and a long succession of La Nina events that sucked heat out of the atmosphere and dumped it in the ocean.

All things being equal, without human greenhouse gas emissions to keep pushing the climate hotter, 2000-2010 would have probably been amazingly cold. To the contrary, 2005 was the hottest year on record and then 2010 beat it by being the new hottest year on record. The stage is now set for another record hot year for the next El Nino year or even the next somewhat warm ENSO neutral year.

But climate change deniers are nothing if not persistent. Their endless parade of cherry picked data makes its march through every corner of the internet. Anthony Watts and Steve Goddard spam nonsense endlessly. Fox News provides special coverage of every snowstorm. The Examiner hosts about a thousand climate change deniers. And, lately, even The Economist appears to have gotten into the act by spuriously speculating that climate sensitivity is less than that estimated by the IPCC.

Given the actual temperature record and the current state of natural variability, anyone with a Google search engine and making an honest attempt to check the facts can find that global warming didn’t stop, the planet didn’t cool, and, sorry Economist, that scientists aren’t saying that climate sensitivity is less than they anticipated. In fact, we find that when accounting for natural variability global warming didn’t slow at all. Even worse, the deep ocean heated up at a rate far faster than was previously anticipated and the Arctic sea ice is disappearing 60-80 years ahead of schedule.

The Economist might have saved itself some embarrassment if it had taken a look at the above graph which takes into account some of the natural climate variables. It might also have further researched some of the climate sensitivity reports it mentions. One model it cited shows a sensitivity of 3.9 degrees after the strong El Nino decade of the 1990s even though it shows a 1.9 degree sensitivity after most recent strong La Nina series. Paleo climate indicates a climate sensitivity of about 4.5 degrees C long term. Climate scientists estimate this sensitivity to be 3 degrees C. Given how conservative estimates for Arctic sea ice melt have proven, it is possible that long-term sensitivity estimates may end up being conservative as well.

The primary drivers of sensitivity, water vapor increases and natural carbon feedbacks have yet to play their hands. So calling the decline of climate sensitivity at this early date and against the vast body of evidence already produced by climate science and which, as mentioned above, is likely to prove conservative, is very unwise at this point. It is also very likely to prove wrong in the end.

In fact, The Economist doesn’t even consider that the last 13 years have had 6 La Nina years, 5 neutral years, and only two El Nino years. One El Nino year — 2005 was the hottest on record. The fact that 2010 was the next new hottest year on record without even being an El Nino year should have raised a few eyebrows. Even the most recent La Nina year, 2012 ranks as the second hottest La Nina year on record. In any case, the above graph and the procession of these years shows no evidence of lowering climate sensitivity or a slowing of the overall warming trend.

The Economist would also do well reading Jeff Master’s recent blog: How to Abuse Statistics: Claim Global Warming Stopped in 1998. Jeff is a former Hurricane Hunter with a PhD in atmospheric sciences. So he knows what he’s talking about. As does the oft attacked and mis-quoted James Hansen. Notably, The Economist starts its own, seemingly unintentional, statistics abuse by coming very close to making the claim that global warming stopped in 1998.

Anyone writing on climate change can save themselves from future embarrassment and retractions by taking a good hard look at work by the above scientists. It also wouldn’t hurt for them to visit the website Skeptical Science. It is one of the best researched sites examining broad issues surrounding climate change on the web. Many of their articles are written or contributed to by leaders in climate science. And they provide an excellent resource for anyone wishing to write credible articles on the subject of climate change. They also provide a wonderful resource for debunking climate change deniers. One that is sorely needed in this age of climate change misinformation.